JPH02170490A - Circuit board of metal core type - Google Patents

Abstract

PURPOSE:To remove noises in a circuit pattern by a method wherein a prescribed laminated region which is formed of a metal substrate, an insulator layer on the substrate and the circuit pattern formed on the insulator layer functions concurrently as a capacitor. CONSTITUTION:An insulator layer 2 of a polyimide-based resin is integrally formed on a metal substrate 1; a ground pattern 3 is integrally formed on a prescribed region face of the insulator layer 2. The pattern 3 is connected electrically to the substrate 1 via an opening 4 which has been made in one part of the insulating layer 2. A circuit pattern 5 is isolated from the pattern 3 and is applied and formed on another region of the insulator layer 2. During this process, an end-part 5a of the pattern 5 uses a region 1a, of the substrate 1, facing it as a counter electrode; a region 2a of the insulator layer 2 is used as a dielectric layer; they are constituted so as to function as a capacitor. Thereby, noises of the pattern 5 can be driven easily to the pattern 3 via this capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a metal core type circuit board, and more particularly to a metal core type circuit board having a configuration in which a metal plate forming a core is used as a conductive path.

(Prior art) In order to improve heat dissipation and mechanical strength of a circuit board, a metal plate is used as a core, at least one main surface of the core is coated with an insulator layer, and a circuit pattern is formed on the surface of the insulator layer. Circuit boards with layered configurations have been developed. This type of metal core type circuit board has attracted a lot of interest from the viewpoint of high-density mounting of electronic components and miniaturization of high-density circuit components. By the way, in this type of metal core type circuit board, attempts have been made to utilize the metal plate forming the core as a conductor. That is, a ground pattern provided in a predetermined area on an insulator layer covering the main surface of a metal substrate is electrically connected to the metal substrate through a hole drilled in the insulator layer, and the metal substrate is set at a ground potential. On the other hand, a circuit board having a structure in which a required circuit pattern is formed on an insulating layer at a distance from the ground pattern has been developed. By the way, in a metal core type circuit board that uses this metal board as a part of the conductor, a capacitor is appropriately attached between the circuit pattern and the ground pattern in order to eliminate or avoid noise on the circuit pattern side. . That is, when electronic components are mounted and mounted on the circuit pattern side, a capacitor element is especially arranged between the circuit pattern and the ground pattern in order to remove or reduce noise observed on the circuit pattern side.

(Problem to be Solved by the Invention) However, the configuration in which a capacitor element is specifically attached between the circuit pattern and the ground pattern in order to remove or reduce noise in the circuit pattern increases the number of components mounted, and the circuit configuration It also becomes more complex. For this reason, the mounting work becomes complicated, and it is difficult to say that it is fully satisfactory in terms of mass production and reliability.

[Structure of the Invention] (Means for Solving the Problems) The present invention has been made in response to the above-mentioned circumstances, and includes a metal substrate that performs the required functions, an insulating layer provided on the metal substrate, and an insulating layer provided on the metal substrate. The present invention is characterized in that a predetermined laminated region formed by the circuit pattern provided on the insulator layer has a capacitor function, and is configured to remove noise in the circuit pattern.

(Function) According to the above structure or means of the present invention, the metal substrate connected to the ground pattern forms one electrode, and also serves as one of the circuit patterns laminated on the metal substrate with an insulating layer interposed therebetween. The part forms the other electrode, and also has a capacitor function by using a part of the insulating layer as a dielectric. In other words, since the circuit pattern and the ground pattern are electrically connected via the integrally formed capacitor, noise generated on the circuit pattern side can be easily removed or avoided. Moreover, since the capacitor is formed integrally with the circuit board, there is no need to separately arrange a capacitor element between the circuit pattern and the ground pattern, and compactness can also be achieved.

(Example) The present invention will be described in detail below with reference to FIG. The figure is a vertical cross-sectional view of the main parts of the metal core type circuit board of the present invention, and 1 is a metal board with a thickness of, for example, 1.5 m.
Steel plate m, 2 is an insulating layer integrally formed on the main surface of the steel plate 1, for example, a polyimide resin layer having a thickness of 0.1 mm.

Reference numeral 3 denotes a ground pattern integrally formed on the surface of a predetermined area of the polyimide resin layer 2, and this ground pattern 3 has an opening (hole) formed by drilling a part of the polyimide resin layer 2. ) 4 to the metal substrate 1. Further, 5 is a circuit pattern that is integrally formed on another area surface of the polyimide resin layer 2 apart from the ground pattern 3, and 6 is arranged or mounted at a predetermined position of the circuit pattern 5. , mounted electronic components such as packaged TC elements, capacitors, resistors, etc. Therefore, the end region 5a of the circuit pattern 5
The region 1a of the metal substrate facing this end region 5a is used as a counter electrode, and the region 2a of the polyimide resin layer 2 interposed between these two-headed regions 5a s 1 a is used as a dielectric layer to function as a capacitor. It is composed of: In other words, the circuit pattern 5 constitutes a desired electronic circuit or circuit device together with the electronic component 6 mounted at a predetermined position of the circuit pattern 5, while the circuit pattern 5 is formed by the end portion 5a of the circuit pattern 5, etc. The structure is electrically connected to the ground circuit pattern 3 via a capacitor 7.

Therefore, the metal core type circuit board of the present invention can be manufactured as follows. First, a metal substrate 1 of a desired size is prepared, and a polyimide resin layer, for example, is applied and formed on the main surface of the metal substrate 1, and then dried and baked to form an insulator layer 2.
form. Next, a portion of the formed insulating layer 2 made of polyimide resin is selectively removed or bored to expose a portion of the metal substrate 1. Note that this part of the metal substrate 1 may be exposed in the formation of the insulator layer 2 by masking the area to be exposed so that the insulator layer 2 is not formed.

After forming the insulating layer 2, a ground pattern 3 is printed using, for example, a conductive paste on the surface of a predetermined region of the insulating layer 2, including a region where a part of the metal substrate 1 is selectively exposed. At this time, the ground pattern 3 is formed so as to be connected to the selectively exposed surface of the metal substrate 1. On the other hand, a desired circuit pattern 5 is printed on the insulating layer 2 using, for example, a conductive paste, apart from the ground pattern 3. In forming this circuit pattern 5, a part of the circuit pattern 5, for example, the end portion on the side of the ground pattern 3 is enlarged so that it can function as an electrode of a capacitor. After printing and forming the ground pattern 3 and the circuit pattern 5 in this way, the ground pattern 3, the circuit pattern 5, and the capacitor 7 interposed between the two patterns 3.5 were integrally formed by drying and baking. A metal core type circuit board is obtained.

In the manufacturing method of the metal core type circuit board described above, an example was shown in which the ground pattern 3 and the circuit pattern 5 are formed by printing conductive paste. After performing selective etching to form the required ground pattern 3 and circuit pattern 5, a part of the insulating layer 2 is removed and the exposed surface of the metal substrate 1 and the ground pattern 3 are bonded with conductive paste, conductive solder, etc. It can also be manufactured using an electrical connection method.

As described above, in the metal core type circuit board according to the present invention, the part 1a of the metal substrate and the part 5a of the circuit pattern formed on the metal substrate 1 via the insulator layer 2a are used as opposing electrodes, respectively, and these opposing electrodes are The insulator layer 2a between 1a and 5a is used as a dielectric to provide a capacitor function. That is, the circuit pattern 5 formed on the metal substrate 1 via the insulator layer 2 is connected to the ground pattern 3 via the capacitor.

Therefore, when necessary electronic components are mounted and mounted on the circuit pattern to form a mounted circuit component or a mounted circuit device, noise that often occurs on the circuit pattern side can be easily removed to the ground pattern side via the capacitor. be done. In other words, when viewed as a mounted circuit device, noise is completely eliminated, reduced or avoided, and excellent required functions are always exhibited.

Although the above configuration example shows the case where the circuit pattern is one layer, it may be a multilayer type in which one or more circuit patterns are formed on the circuit pattern with an insulating layer interposed therebetween.

[Effects of the Invention] As can be seen from the above description, the metal core type circuit board according to the present invention has a capacitor integrally incorporated therein for removing or avoiding noise on the circuit pattern side, so that it can be configured, for example, in a mounted circuit device. Even in this case, malfunctions caused by the noise are completely suppressed. In addition, there is no need to add any complicated work processes to the manufacturing or configuration, and there is no separate provision of a capacitor element, making it compact.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the structure of a metal core type circuit board according to the present invention. 1...Metal substrate 2...Insulator layer 3...Ground pattern 4...Drilling hole 5...Circuit pattern 6...Electronic component 7...Capacitor applicant Toshiba Corporation

Claims (1)

[Claims] A metal substrate, an insulating layer covering at least the main surface of the metal substrate, and a hole formed by drilling a part of the insulating layer to electrically connect the metal substrate to the metal substrate. A ground pattern to be connected, and a circuit pattern formed on the insulator layer electrically isolated from the ground pattern, and the circuit is provided in a predetermined stacked area of the metal substrate-insulator layer-circuit pattern. A metal core type circuit board characterized by having a capacitor function that removes noise in the pattern.